MY EARLIER ADVICE ON HOOKING UP A BIG UPS to power your modem/wireless router is criticized by reader Erik Carlseen, who emails:

Argh!!!!! (Sorry, I see this bad advice followed all over the place). El-cheapo UPSs like this usually give you very little time to work with, then their batteries go bad within a few years and then at that point they’re basically just a very large and heavy surge suppressor. The unit you linked – even when brand new – will give about 10-15 minutes of run-time under a typical home office load (a bit more if a notebook is used instead of a desktop). Most of the time, people plug them in and forget about them, and then when they’re actually needed they don’t do much good.

The following advice is for people who have actual value for their time and data…

You’re better off putting on the correctly-sized, expandable UPS and then adding external battery packs to suit your needs. Buying a “bigger” UPS just oversizes the electronics far, wasting budget dollars on purchasing them and battery power when they’re in use. The value is in the additional run-time, so put your money there instead. Something like this.

Pricier, but the quality is excellent, it’s got more battery (about twice the run-time), less wasted capacity, and it recharges almost three times faster. I typically get 8-12 years of use out of models from this manufacturer, changing the batteries out every 4 years.

You can also slap on up to five of these external battery packs (for a total of about 12 hours of runtime with a typical desktop PC, 40 hours of notebook+cable modem & router).

See the chart here for more info.

Yes, it’s expensive, but if the data and uptime are actually important they get the job done. Figuring out one’s cost and likelihood of downtime combined with the flexibility of one’s time (can I do something else now and catch up on work later?) and making the appropriate trade-offs is left as an exercise for the reader :-)

If you need to power multiple computers (say, for a small office), then size up the electronics (leaving appropriate room for growth), and add battery packs to taste.

I appreciate the advice, but my 1500VA APC Back-UPS unit has run my cable modem / wireless setup for most of a day with lots of power left. I’m sure this stuff’s better, but I’m not sure it’s worth if for most people. Now I’ve got a similar setup backing up the PJTV studio, but maybe that would be worth expanding on. Then again, my power doesn’t go out much.

Meanwhile, several readers suggest getting a big, or a medium-sized, power inverter. Unless you buy a pretty expensive one, though, the power those put out is kind of iffy for some electronics. Of course, if you’re really serious you can go with something like this.